(1) Field of the Invention
The present invention relates to an oil filter and oil cooler mounting arrangement for a four-cycle, inline multi-cylinder motorcycle engine having a multiple number of exhaust pipes.
(2) Description of the Prior Art
In many motorcycles having a four-cycle multi-cylinder engine mounted thereon, an inline multi-cylinder engine unit having its multiple cylinders inclined forwards with its crankshaft extending widthwise across the bodywork is arranged and suspended in the lower front part of the motorcycle bodywork. In the exhaust system of such an engine, exhaust pipes connected to exhaust ports on the upper front side of the forward tilting cylinders extend from the front part of the engine unit downwards and further are bent around the bottom of the engine unit and directed to the rear so that they are connected together or individually to the muffler arranged in the rear part of the motorcycle body.
In a motorcycle of the above type, in order to minimize the sideward bulges of the body, the oil filter and the oil cooler of the engine unit are attached to the front part of the engine case. In particular, there are motorcycles with their bodywork totally covered by a fairing in which the oil filter and oil cooler are arranged side by side in their front view.
In this case, the exhaust pipes are laid out in front of and under the oil filter and oil cooler. Therefore, as matters stand, the exhaust pipes will interfere with the oil filter and the oil cooler when they need to be replaced, producing difficulties in mechanical maintenance.
As a prior art oil filter layout configuration of an engine unit of this type, it is possible to provide a configuration by the combination of the disclosure of Japanese Patent Application Laid-Open Hei 7 No.11955 wherein the oil cooler is arranged at the bottom of the oil filter and that of Japanese Patent Application Laid-Open Hei 1 No.211609 wherein a multiple number of exhaust pipes located in front of the oil filter are separated to the sides forming a space therebetween.
However, the combination of these prior arts means that the oil cooler with an oil filter attached in the front thereof should be attached to the engine. Therefore, in order to avoid interference with the exhaust pipes, both the oil cooler and the oil filter have to be compact, or of a small volume. Since the performance of cooling the oil lowers if the volume of the oil cooler is small, oil film may be used up or cavitation might occur when the engine is run at a high speed over a long period.
In contrast, there is a method in that the oil filter and oil cooler are mounted side by side in the lower front part of the engine(see Japanese Patent Application Laid-Open Hei 11 No.182260). However, it is defined in the publication of this motorcycle that the projected ends of the oil filter and oil cooler are located within the space enclosed by the crankcase and the exhaust pipes arranged in front of the crankcase. Therefore, when tools are inserted into the space to fasten or unfasten bolts etc., upon attachment and detachment of the oil filter and oil cooler, turning of the tools interferes with the exhaust pipes, so that the exhaust pipes need to be detached, resulting in poor work performance.
The present invention has been devised in view of the above problems, and it is therefore an object of the present invention to provide an oil filter and oil cooler mounting arrangement for a four-cycle motorcycle engine, which permits fastening and unfastening tools to be inserted and turned upon attachment and detachment of the oil filter and oil cooler without inference of the exhaust pipes, providing improved work performance.
In order to achieve the above object, the present invention is configured as follows:
In accordance with the first aspect of the present invention, an oil filter and oil cooler mounting arrangement for a four-cycle engine for use in a motorcycle has an inline multi-cylinder engine which comprises: a crankshaft laid out widthwise across the bodywork and mounted in the front lower part of the bodywork; an oil pan having both side surfaces inclined; and a multiple number of exhaust pipes extended from the front upper part of the engine to the lower part of the engine and bent toward the rear while being split to the left and right along the inclined side surfaces, and is characterized in that an oil filter and oil cooler are arranged side by side and projected forwards in the lower front part of the engine; the oil cooler has its fastening sites at both sides when viewed from the front; and the exhaust pipes are arranged so that spacings are formed between the two adjacent exhaust pipes, at least, in front of the center of the oil filter and in front of the inner fastening sites of the oil cooler, respectively.
In accordance with the second aspect of the present invention, the oil filter and oil cooler mounting arrangement for a four-cycle engine for use in a motorcycle having the above first feature is characterized in that at least one of the exhaust pipes is extended vertically in front of and between the center of the oil filter and the inner fastening sites of the oil cooler.
In accordance with the third aspect of the present invention, the oil filter and oil cooler mounting arrangement for a four-cycle engine for use in a motorcycle having the above first feature is characterized in that a cooling water hose is arranged close to the outer side, with respect to the bodywork width, of the oil cooler and the outer fastening sites of the oil cooler are arranged at positions above and below the cooling water hose, when viewed from the front.
In accordance with the fourth aspect of the present invention, the oil filter and oil cooler mounting arrangement for a four-cycle engine for use in a motorcycle having the above second feature is characterized in that a cooling water hose is arranged close to the outer side, with respect to the bodywork width, of the oil cooler and the outer fastening sites of the oil cooler are arranged at positions above and below the cooling water hose, when viewed from the front.
In accordance with the fifth aspect of the present invention, the oil filter and oil cooler mounting arrangement for a four-cycle engine for use in a motorcycle having one of the above first through fourth features is characterized in that the exhaust pipes are positioned so that the spacings between the adjacent exhaust pipes are positioned in front of the oil filter center and in front of the inner and outer fastening sites of the oil cooler, respectively.
According to the present invention, since the oil filter and oil cooler are arranged side by side and projected forwards in the lower front part of the engine, it is possible to enlarge the oil filter and oil cooler in both height and in radius, and hence enlarge their capacities without having to worry about any obstacles.
The oil cooler has fastening sites at both sides when viewed from the front and the exhaust pipes are arranged so that spacings between two adjacent exhaust pipes are positioned, at least, in front of the center of the oil filter and in front of the inner fastening sites of the oil cooler, respectively. Since the oil filter and oil cooler are projected forwards and arranged at the lower front of the engine, it is necessary to form spacings between the exhaust pipes through which tools for attachment and detachment can be inserted. This is why the spacings between two adjacent exhaust pipes are positioned in front of the center of the oil filter and in front of the inner fastening sites of the oil cooler, respectively. In this case, since the oil filter is attached or detached by fitting a tool over the oil filter and turning the tool, it is necessary to provide the insert space for the tool. As to the oil cooler, the oil cooler has fastening sites at both sides thereof when viewed from the front. The fastening sites on the outer side are accessible to the tool which is inserted from the side of the engine, whereas the fastening sites on the inner side are not accessible to the tool, which is inserted from the side of the engine, because they are enclosed on both sides by the oil filter and oil cooler. This is why the spacing is positioned between the two exhaust pipes in front of the inner fastening sites of the oil cooler so as to allow the tool to be inserted.
In the present invention, since, regardless of the number of cylinders, at least one of the exhaust pipes is extended vertically in front of and between the center of the oil filter and the inner fastening sites of the oil cooler, it is possible to arrange the spacings between the exhaust pipes in front of the center of the oil filter and in front of the inner side fastening sites of the oil cooler.
In order to secure high enough a capacity of the oil cooler for improved cooling performance, it is necessary to extend the oil cooler outwards as closely to the engine width as possible. The engine hose connecting the radiator and the water pump is preferably arranged as inwardly (closely to the oil cooler) as possible in order to assume a large bank angle. As a result, since the hose is arranged close to the oil cooler, the cooling water hose is positioned close to the outer side, with respect to the bodywork width, of the cooler, and the outer fastening sites of the oil cooler are arranged at upper and lower positions set away from the cooling water hose when viewed from the front, thus providing the space for the tool to be inserted for fixing.
In addition to the spacings formed in front of the oil filter center and in front of the inner fastening sites of the oil cooler, another spacing may be formed between the exhaust pipes in front of the outer fastening sites of the oil cooler, so that the tool can be inserted from the spacing. This configuration further improves the work performance.